My 55 presently has a 351 with a wrong cam so I bumped the gears from 2.79 to 3.00 and the motor is spinning more then I thought at 70 on the highway,those gears perked it up some around town but not as much as a I would like so I am thinking about going with 3.25 gears and a AOD with a Lentech valve body. I wanted to got with a FMX so I could use the original type starter but the AOD is starting to sound good so I can have a gear so it will run good around town and go comfortably down the highway.

Butchering up everything I can get my hands on in Dayton Ohio

I'm using a AOD behind my Y-Block with a 3.9 gear ratio. The engine turns about 2200 in overdrive at 60-65mph. I'm not sure if the 3.25 will be enough. I plan to put a set of 4:10's in it in the spring. Chuck

Y's guys rule!
Looking for McCullouch VS57 brackets and parts. Also looking for 28 Chrysler series 72 parts. And early Hemi parts.

MoonShadow, 292 w/McCulloch, 28 Chrysler Roadster, 354 Hemi)
Manchester, New Hampshire

If 3.25s wont cut it will 3.55s work.

Butchering up everything I can get my hands on in Dayton Ohio

I don't know for sure if the 3:25's wouldn't work. Just my experience with the AOD. Chuck

Y's guys rule!
Looking for McCullouch VS57 brackets and parts. Also looking for 28 Chrysler series 72 parts. And early Hemi parts.

MoonShadow, 292 w/McCulloch, 28 Chrysler Roadster, 354 Hemi)
Manchester, New Hampshire

Do you actually know how fast the engine is turning at 70?


Lawrenceville, GA

About 2500 for my setup with the 3:80's. Chuck

Y's guys rule!
Looking for McCullouch VS57 brackets and parts. Also looking for 28 Chrysler series 72 parts. And early Hemi parts.

MoonShadow, 292 w/McCulloch, 28 Chrysler Roadster, 354 Hemi)
Manchester, New Hampshire

In case anyone is interested the formula is; rpm = mph x gear ratio x 336 / tire diameter

"The Master Cylinder"

Enjoying life at the beach in SOCAL

Oh, that was at Jeff.

For that formula, if you have overdrive, also multiply the overdrive ratio to find the overdrive rpm.


Lawrenceville, GA